MC-20250: Advanced search causes exception

Author: Joan He

app/code/Magento/CatalogSearch/Model/ResourceModel/Advanced/Collection.php

@@ -393,6 +393,7 @@ private function getSearchResultApplier(SearchResultInterface $searchResult): Se
             /** This variable sets by serOrder method, but doesn't have a getter method. */
             'orders' => $this->_orders,
             'size' => $this->getPageSize(),
+            'currentPage' => (int)$this->_curPage,
             ]
         );
     }